P2.B038: Long Term Longitudinal Assessment of Ventricular Function after Transcatheter Pulmonary Valve Implantation in Tetralogy of Fallot with or without Pulmonary Atresia: A Speckle Tracking Echocardiography Study

Background: Surgical repair of tetralogy of Fallot (TOF) with or without pulmonary atresia (PA) often leads to chronic pulmonary regurgitation (PR). Transcatheter pulmonary valve implantation (TPVI) is performed to restore pulmonary valve function with the intent to reverse the right ventricle remodeling. However, data on long-term ventricular function post-TPVI is lacking. Therefore, we aimed to study the long-term effect of TPVI on ventricular function.

Methods: In a retrospective longitudinal study, we included patients with TOF or TOF/PA and chronic severe PR who underwent TPVI at a tertiary children’s hospital between 2012-2022.

The right ventricular (RV) free wall strain (RVFWS), RV global longitudinal strain (RVGLS), and left ventricular (LV) global longitudinal strain (LVGLS) were assessed from the apical 4-chamber view using vendor-independent TomTec Imaging software at four-time points: pre-TPVI (Time point 1), post-TPVI: 1 month (Time point 2), 1 year (Time point 3), and 4 years (Time point 4). Paired t-tests were utilized to compare RVFWS, RVGLS, and LVGLS at time point 1 with subsequent time points. Pearson correlation analysis was performed between RVFWS at time point 1, and biventricular indices from cardiac MRI and cardiac catheterization. A p-value ≤ 0.05 was considered significant.

Results: Our cohort included 30 patients, 17 males (56%) with a median (IQR) age at the time of TPVI of 18 (16.36) years. The RVFWS and RVGLS were subnormal at time point 1 and did not improve at time points 2, 3, and 4. Conversely, the LVGLS was subnormal at time point 1, did not change at time points 2 and 3 but improved at time point 4 (Table 1). The RVFWS at time point 1 inversely correlated with the indexed RV volume and directly correlated with LV ejection fraction both measured by cardiac MRI. Additionally, the RVFWS at time point 1 inversely correlated with RV systolic pressure measured by catheterization (Table 2).

Conclusion: Patients with TOF or TOF/PA and chronic severe PR demonstrated no significant improvement in RV function up to 4 years post TPVI although there was improvement in LV systolic function. RV volume at TPVI negatively influenced the RV function prior to TPVI. Therefore, our study raises the need to address the RV volumetric changes and timing of TPVI if the intent of intervention is to restore the RV function.